The images and texts once considered as a "breach of good morals" have got France's - mostly approving - critics hot under the collar. And the show is so popular that Libération has reported overcrowding; the number of visitors has reached 600 a day, twice that of an typical exhibition.

Le Figaro described the exhibition as "occasionally of a breath-taking beauty and emotion". Many commentators remarked on the incredibly rare event in Paris's culture world: a ban on under-16s.

The Library has also shown some of the works in a disused metro station which passengers glimpse as they drive through: they have 7 seconds to enjoy the huge posters reproducing suggestive details extracted from salacious engravings. But how to react when walking round the exhibition lined with libertine novels, engravings of sex gods or pictures of the female anatomy known as the origin of the world? It does seem a bit weird watching an explicit 1920s porn film set in a dress-maker's shop in the national library. But the mood is one of quiet contemplation, where the erotic is taken very seriously.

The exhibition is not only a juxtaposition of erotic pieces, or a celebration of lust and sex through the ages. It also explains particular moments of French literature and social history.

First, the characters Justine and Juliette, heroines of the famous Marquis de Sade, plunge the visitor into an era of total subversion, where the sensual is mixed with cruelty. Some original editions of his texts are on display, most of them written in prison.

Then, we discover secret underground publishing from the 19th century when censorship became more stringent, the first pornographic pictures appeared and Charles Baudelaire scandalised France with Les Fleurs du Mal.

As for the 20th century, there is Apollinaire's erotic novel Les Onze Mille Verges, followed by works by Man Ray, Aragon, George Bataille and Jean Genet.

Despite the academic atmosphere among the visitors, there are whispers (of embarrassment? Desire?) and discreet laughter.

After looking at an engraving showing a couple having acrobatic sex in the branches of a tree, a middle-aged woman exclaimed: "It's not very practical, is it?". Another was astonished by the oversized genitals of the men in the Japanese drawings.